There is a fastening tool for a string body that is generally called a cord lock. The fastening tool includes a female member and a male member having through-holes through which the string body is inserted, and an urging device urging the male member in a direction in which the male member is removed from the female member. When a push-in operation for the male member is stopped by the urging force from an urging device, the male member is moved from a non-fastening position through which the string body is inserted without frictions in the through-hole of the female member and the through-hole of the male member or with small frictions therein, and the fastening tool is fastened to the string body with the through-hole of the female member and the through-hole of the male member that are displaced from each other. However, when the fastening tool, for example, is fastened to a drawstring of an opening of a glove serving as a fitting object, a push-in operation for the male member may not be easily performed by the other hand with a glove. For this reason, a fastening tool that is designed such that a release string fixed to a glove is attached to a deep portion of a male member is proposed. (see Patent Document 1) According to the fastening tool, the male member can be moved to the non-fastening position by a drawing operation for the release string. In this manner, the fastening position of the fastening tool on the drawstring can also be changed to loosen the tightened drawstring. However, since the female member has a margin for the glove, when the release string is only simply drawn, releasing the fastening state of the fastening tool to the drawstring may be difficult.